In N
ew Z
eala
nd: R
esen
e Pa
ints
Lim
ited,
Vog
el S
treet
, PO
Box
3824
2, W
ellin
gton
Mai
l Cen
tre, L
ower
Hut
t 504
5 Ph
one
0800
RES
ENE
(737
363
) F
ax (0
4) 5
77 0
600
Em
ail a
dvice
@re
sene
.co.n
z or v
isit w
ww.
rese
ne.co
.nz
In A
ustr
alia
: Res
ene
Pain
ts (A
ust)
Limite
d, 7
Pro
duct
ion
Ave,
PO B
ox 7
85, A
shm
ore
City,
Que
ensla
nd 4
214
Phon
e 1
800
738
383
Fa
x 18
00 0
64 9
60
Em
ail a
dvice
@re
sene
.com
.au
or vi
sit w
ww
.rese
ne.co
m.a
u
acces s spec i f i c a t i on i n fo rmat ion on l i ne a t www. re sene. com.au o r www. re sene. co.n zm in im i se the e f f e c t o f you r p ro j e c t on the env i ronment – see the Resene webs i t e
If in doubt about any aspect of your specification please contact Resene.
D83Feb 2010
General
Concrete is the complex reaction product of aggregates, silica sand and calcium silicates present in
cement. Lime is produced during the setting reaction that slowly further reacts with the silica sand
to form more cement. This lime production accounts for the high initial alkalinity of concrete and is
influenced by the amount of water added, type of aggregate and additives used. This high alkalinity
may saponify (lime burn) many alkyds and PVAs. It is recommended that concrete is left for 28 days
before painting with alkali-resistant paints, such as 100% waterborne finishes, three months for
PVAs and one year for solventborne finishes. Excess lime may migrate to the surface as a milky
deposit, efflorescence or lime staining. Resene Limelock (see Data Sheet D809) is recommended on
all fresh plaster to prevent lime staining. Resene Limelock (see Data Sheet D809) is a preparatory
coating designed to cure and seal cementitious surfaces by retaining moisture necessary to achieve
cure and trapping free lime, minimising downtime between the completion of plastering and
commencement of painting.
The cement matrix is slowly eroded by acids normally present in rain, so that old concrete has a
weak, unbound layer of sand on the surface.
The above holds true for all concrete products although the different forms do have some
individual differences:
(a) Cement renders (including EIFS, rough cast and stucco): May have weak surface
layers due to water loss from relatively thin layers leading to poor curing. Many renders
have added lime leading to very high alkalinity.
(b) Concrete masonry: The very low slump mixtures used in this area reduce alkalinity but
increase porosity. Mortars used for jointing and reinforcing are generally highly alkaline.
(c) Concrete roofing tiles: The factory applied cementitious coating breaks down on extended weathering to a fine powder which, if
untreated, provides a weak substrate for paint.
(d) Fibre reinforced cement: Low incidence of alkalinity and efflorescence in flat sheet; greater danger in moulded sheet. Some possibility
of mould release oil contamination.
(e) Glass reinforced cement (GRC): These very dense and glossy surfaces may also be contaminated with form release oils
and defoamers.
(f) Old fibre reinforced cement (prior to 1982): May contain asbestos. Contact local Health Authorities for advice on
preparation work.
(g) Poured concrete: More likely to have efflorescence and laitance due to higher slump mixes. Strong likelihood of form oils and/or
curing agents being present.
Surface preparation
New concrete, concrete masonry and fibre reinforced cement
D83.1 Remove powdery layers and efflorescence
Remove any powdery layers, laitance or efflorescence by vigorous wire brushing or preferably waterblasting. Sand off any protruding
fibres from fibrous cement.
D83.2 Degrease and clean surfaces
Thoroughly degrease by scrubbing or brushing down with Resene Paint Prep and Housewash (see Data Sheet D812) to remove all dirt,
dust, grease, chalk, cobwebs and other contaminants. Rinse clean with copious amounts of clean water and test surface is degreased
by wiping with clean cotton wool. Repeat process if necessary.
Continued over
Cementitious surfaces
Cement render (Exterior Insulation and Finishing
System (EIFS), rough cast, stucco), concrete, concrete
block, fibre reinforced cement boards,
glass reinforced cement and tilt slab
Referred to in Resene specification sheets:
1 Cementitious surfaces 17 Waterproofing membranes 18 Flooring systems 19 Anti-graffiti systems 20 Textured and specialist coatings
For smoke damaged surfaces see D86
For repaints see D87
Continued
In New Zealand: Resene Paints Lim
ited, Vogel Street, PO Box 38242, Wellington M
ail Centre, Lower Hutt 5045
Phone 0800 RESENE (737 363) Fax (04) 577 0600 Email advice@
resene.co.nz or visit ww
w.resene.co.nzIn Australia: Resene Paints (Aust) Lim
ited, 7 Production Ave, PO Box 785, Ashmore City, Queensland 4214
Phone 1800 738 383 Fax 1800 064 960 Email advice@
resene.com.au or visit w
ww
.resene.com.au
acces s spec i f i c a t i on i n fo rmat ion on l i ne a t www. re sene. com.au o r www. re sene. co.n zm in im i se the e f f e c t o f you r p ro j e c t on the env i ronment – see the Resene webs i t e
If in doubt about any aspect of your specification please contact Resene.
Printed on environmentally responsible paper, which complies with the requirements of environmental management systems FSC Chain of Custody and ISO14001, using vegetable-based inks. Please recycle.
D83
D83.3 Test for moisture
Tape a 0.1mm clear plastic sheet (45cm x 45cm) to the concrete surface. Taping must provide an airtight seal between the concrete
and plastic sheet. After 24 hours check the underside of the sheet for signs of condensation. Darkening of the concrete covered by
the plastic sheet compared to surrounding areas also indicates the presence of moisture. If moisture is detected, allow an additional
drying/curing time of 14 days and repeat test. If moisture is detected on second test, the surface cannot be successfully coated. A
moisture test is not required if Resene Limelock (see Data Sheet D809) is being applied.
D83.9 Seal thin plasters
Resene Limelock (see Data Sheet D809) is recommended on all fresh plaster to prevent lime staining. Resene Limelock (see Data Sheet
D809) is a preparatory coating designed to cure and seal cementitious surfaces by retaining the moisture necessary to achieve cure
and trapping free lime, minimising the downtime between the completion of plastering and commencement of painting. Apply one
coat of Resene Limelock (see Data Sheet D809) over the fresh substrate and allow to dry. Evenly coat all fresh cementitious surfaces
to ensure uniform curing and that free lime cannot be transferred through weak points. When dark, heat absorbing topcoats are
planned, it is prudent to wait seven days before painting. If Resene Limelock (see Data Sheet D809) is applied immediately following
plastering, no surface preparation is necessary. If the surface has been allowed to weather, some surface preparation may be required,
as for fibre reinforced cement.
Old concrete, concrete masonry, fibre reinforced cement, new and old cement renders and weathered roof tiles
In order to assess the condition of these surfaces prior to painting, scratch the surface with a penknife blade - if the surface can be scratched off
as a powder the whole area must be thoroughly cleaned.
D83.1 Remove powdery layers and efflorescence
Remove any powdery layers, laitance or efflorescence by vigorous wire brushing or preferably waterblasting. Sand off any protruding
fibres from fibrous cement.
Special attention needed
Fibre reinforced cement may contain asbestos. The removal and/or disposal of materials containing asbestos (or just the cleaning down
of them) may require special permission and a licence. Contact your local Council to determine your obligations under their bylaws.
Free asbestos is likely to be released during surface preparation and therefore suitable dust masks or respirators must be worn by
all operators involved in surface preparation and disposal of waste. Special care must be taken to contain all debris and this must
be kept wet and disposed of in a landfill. This material must not be left to dry out. Disconnect downpipes from asbestos roofs before
starting work.
D83.2 Degrease and clean surfaces
Thoroughly degrease by scrubbing or brushing down with Resene Paint Prep and Housewash (see Data Sheet D812) to remove all dirt,
dust, grease, chalk, cobwebs and other contaminants. Rinse clean with copious amounts of clean water and test surface is degreased
by wiping with clean cotton wool. Repeat process if necessary.
D83.4 Remove all moss and mould
Thoroughly clean down to remove all loosely adhered material. Treat areas of moss or mould infestation with Resene Moss & Mould
Killer (see Data Sheet D80) correctly diluted with clean water. Leave for up to 48 hours to achieve full kill. For heavy infestations
further applications may be needed. Wash thoroughly with clean water to remove residues.
D83.5 Waterblast 3000 psi
Carefully waterblast at 3000 psi to remove all dirt, chalk, moss and mould residue and any other contaminants. Allow the surface to
dry out for at least 24 hours.
D83.6 Seal surfaces
Allow to thoroughly dry then seal with a full coat of Resene Concrete Primer (see Data Sheet D405) on sound concrete or Resene
Sureseal (see Data Sheet D42) or Resene Waterborne Smooth Surface Sealer (see Data Sheet D47a) on weathered concrete.
Continued over
In N
ew Z
eala
nd: R
esen
e Pa
ints
Lim
ited,
Vog
el S
treet
, PO
Box
3824
2, W
ellin
gton
Mai
l Cen
tre, L
ower
Hut
t 504
5 Ph
one
0800
RES
ENE
(737
363
) F
ax (0
4) 5
77 0
600
Em
ail a
dvice
@re
sene
.co.n
z or v
isit w
ww.
rese
ne.co
.nz
In A
ustr
alia
: Res
ene
Pain
ts (A
ust)
Limite
d, 7
Pro
duct
ion
Ave,
PO B
ox 7
85, A
shm
ore
City,
Que
ensla
nd 4
214
Phon
e 1
800
738
383
Fa
x 18
00 0
64 9
60
Em
ail a
dvice
@re
sene
.com
.au
or vi
sit w
ww
.rese
ne.co
m.a
u
acces s spec i f i c a t i on i n fo rmat ion on l i ne a t www. re sene. com.au o r www. re sene. co.n zm in im i se the e f f e c t o f you r p ro j e c t on the env i ronment – see the Resene webs i t e
If in doubt about any aspect of your specification please contact Resene.
Printed on environmentally responsible paper, which complies with the requirements of environmental management systems FSC Chain of Custody and ISO14001, using vegetable-based inks. Please recycle.
Continued
D83Feb 2010
Smooth/glossy concrete and glass reinforced cement (GRC)
As for old concrete, concrete masonry etc except replace D83.6 with D83.7 below:
D83.7 Seal smooth/glossy surfaces
Allow surface to thoroughly dry out, then seal with a full coat of Resene Waterborne Smooth Surface Sealer (see Data Sheet D47a)
on GRC or Resene Concrete Primer (see Data Sheet D405) on glossy/smooth concrete.
Concrete floors
Floors are prone to a wide range of contamination, so surface preparation is the critical factor in achieving a long lasting paint system. New
concrete floor slabs must be allowed to cure for a minimum of 28 days prior to painting. The preferred surface preparation is by diamond grinding
or captive shot blasting. An alternative method is acid etching (refer D83.8 below). Some new floors may have had a curing membrane applied
or may contain additives that harden the surface. These treatments result in a surface that is usually resistant to dilute acids and that requires
alternative preparation by mechanical abrasion or captive shot blasting. All concrete floors must be checked for excess moisture before coating.
In the case of new concrete the test must be carried out after the minimum recommended curing period.
Refer above for the following surface preparation clauses:
D83.1 Remove powdery layers and efflorescence
D83.2 Degrease and clean surfaces
D83.3 Test for moisture
D83.4 Remove all moss and mould
D83.5 Waterblast 3000 psi
D83.6 Seal surfaces
D83.7 Seal smooth/glossy surfaces
D83.8 Acid etch
Before applying the acid etch solution the concrete surface must be free of dirt, dust, loose material, grease, fat and oil. Remove loosely
adhering contaminants by brushing with a clean stiff-bristled broom or vacuuming with a heavy duty industrial vacuum cleaner.
Pre-wet concrete surface and either brush or vacuum off excess surface water. Uniformly apply etching solution to damp surface using
a plastic watering can. The etching solution may be either hydrochloric acid diluted with six parts by volume of water or phosphoric
acid diluted with ten parts by volume of water. Bubbling should be immediately evident over the entire surface. If this is not the case
re-treat with suitable detergent and repeat the acid etching step.
Scrub the acid wetted surface with a stiff nylon brush when the etching solution bubbling begins to subside (5-15 minutes). Rinse off
with copious quantities of clean water and at the same time scrub with a stiff broom to remove concrete salts.
Etching should produce a concrete surface that is clean and has a slightly roughened profile. If desired surface roughening is not
achieved, repeat the etching procedure. After the desired surface profile is achieved, flush with copious quantities of clean water
until the pH of surface washings is neutral or slightly alkaline. Allow to dry. Vacuum removal of surface water will aid drying. When
dry, vacuum to remove all acid/concrete reaction by-products and loosened aggregate.
Avoid any contamination of the etched surface and paint preferably within three days.